IP with a smooth change in polarity. A simple circuit for obtaining a bipolar power supply from a unipolar power supply. Selecting a bipolar power supply circuit.
The peculiarity of this power source is that by rotating the control knob you can not only change the output voltage, but also its polarity. Practically adjustable from +12V to - 12V. This is achieved thanks to the slightly unusual inclusion of stabilizers of a bipolar power supply, so that both stabilizers are regulated using one variable resistor.
The schematic diagram is shown in the figure. The rectifier is bipolar, made according to a standard circuit on a T1 transformer with a secondary winding tapped from the middle, a diode bridge VD 1 and capacitors C1 and C2. As a result, its output produces a bipolar voltage of +-16.., 20V. This voltage is supplied to two transistor stabilizers VT 1 and VT 3 (positive voltage regulation) and on transistors VT 2 and VT 4 (negative voltage adjustment). The difference from the standard bipolar circuit is that the outputs of the stabilizers are connected together, and that one common variable resistor is used to regulate the voltage R5. Thus, if the slider of this resistor is installed exactly in the middle, and the voltage across it relative to the common wire is zero, then both stabilizers are closed, and the voltage at the output of the circuit is also zero. Now, if the engine begins to move towards positive voltages (up in the circuit), the positive voltage stabilizer on the transistors begins to open VT 1 and VT 3, and a negative voltage stabilizer(VT 4 and VT 2) still remains closed. INAs a result, the output voltage is positive. Now, if the slider is moved in the direction of negative voltages (down the circuit), the positive voltage at the circuit terminal will decrease in the middle position R 5 the voltage will become zero. The positive voltage regulator will close. If the engine is moved further in the same direction, the negative voltage stabilizer on the VT 2 and VT 4 (in this case, the positive voltage stabilizer will be closed) and the negative voltage at the output will increase.
The design uses a ready-made transformer"TAIWAN" with a power of 10 W, producing two alternating voltages of 12 V each on the secondary winding.
The capacitances of capacitors C1 and C2 should not be less than 1000 µF; it must be taken into account that the level of ripple at the output depends on them. Zener diodes can be any low-power voltage 12V. The KT817 transistor can be replaced with KT815, KT807, KT819. Transistor KT816 - on KT814, KT818. Transistors KT502 and KT503 can be replaced, respectively, with KT361 and KT315. You can use another rectifier bridge, for example KTs402, or assemble it from diodes like D226 or KD105.
Transistors VT 1 and VT 2 need to be placed on small heat sinks.
Scheme:
The peculiarity of this power source is that by rotating the control knob you can not only change the output voltage, but also its polarity. In practice, it can be adjusted from +12V to -12V. This was achieved thanks to the unusual inclusion of stabilizers of a bipolar power supply, so that both stabilizers are regulated using one variable resistor.
Device:
The circuit diagram is shown in the figure above. The rectifier is bipolar, made according to a standard circuit on transformer T1 with a secondary winding tapped from the middle, diode bridge VD1 and capacitors C1 and C2. As a result, its output produces a bipolar voltage + - 16...20V. This voltage is supplied to two stabilizers on transistors VT1 and VT3 (positive voltage regulation) and on transistors VT2 and VT4 (negative voltage regulation). The difference from the standard bipolar circuit is that the outputs of the stabilizers are connected together, and that one common variable resistor R5 is used to regulate the voltage. Thus, if the slider of this resistor is installed exactly in the middle, and the voltage across it relative to the common wire is zero, then both stabilizers are closed, and the voltage at the output of the circuit is also zero. Now, if the engine begins to move towards positive voltages (up the circuit), the positive voltage stabilizer on transistors VT1 and VT3 begins to open, and the negative voltage stabilizer (VT4 and VT2) still remains closed. As a result, the output voltage is positive. Now, if the slider is moved in the direction of negative voltages (down the circuit), the positive voltage at the circuit terminal will decrease and in the middle position of R5 the voltage will become zero. The positive voltage regulator will close. If the engine is moved further in the same direction, the negative voltage stabilizer on VT2 and VT4 will begin to open (while the positive voltage stabilizer will be closed) and the negative voltage at the output will increase.
Details:
The design uses a ready-made TAIWAN transformer with a power of 10 W, which produces two alternating voltages of 12 V each on the secondary winding. The capacitances of capacitors C1 and C2 should not be less than 1000 μF, it must be taken into account that the level of ripple at the output depends on them. Zener diodes can be any low-power for a voltage of 12V. The KT817 transistor can be replaced with KT315, KT807, KT819. The KT816 transistor can be replaced with KT814, KT818. The KT502 and KT503 transistors can be replaced, respectively, with KT361 and KT315. You can use another rectifier bridge, for example KTs402, or assemble it from diodes. type D226 or KD105 Transistors VT1 and VT2 need to be placed on small heat sinks. Based on this circuit, you can make a more powerful source that produces a higher maximum voltage. You just need to use more powerful transistors, a more powerful transformer that produces a higher voltage, as well as other zener diodes and. rectifier bridge. Everything is the same as for a conventional power source.
Radioconstructor No. 1 2000 p. 25
- Stability – over 8 hours of operation under constant conditions:
- Temperature coefficient:
- At your request, we can prepare certain blocks with even higher stability.
This option only applies to new blocks. No further modification is possible.
Reduced output ripple
For some series, reduced ripple can be achieved through smoothing filtering. This option only applies to new blocks. No further modification is possible. To order with this option:
- For MCP and HCP up to 35W: 1 x 10-5 + 10mV p-p.
- For MCP and HCP 140W to 700W: 1 x 10-5 + 20 mV p-p.
- For MCP and HCP from 1400W: 1 x 10-5 + 100mV p-p.
Lower stored energy
Especially for gas-discharge processes, arc and similar consuming devices with a negative dynamic resistance characteristic, the amount of accumulated energy can be reduced by a smaller output capacitance. For these blocks, the ripple will be higher, up to 1%.
High resolution digital meters
Instead of a standard digital voltmeter with a display of max. "1999", a DVM with a higher resolution can be offered.
Digital meters with display “4.5” instead of “3.5” can be built into all serial devices. This replacement is also possible later at our factory. Digital meters with display “6” can only be installed in new units, giving them increased stability. Units type MCP or HCP are equipped as standard with digital meters with a “4.5” display.
Increased tuning accuracy
An optional ten-turn potentiometer for fine-tuning current and/or voltage allows for up to 100-fold increase in resolution. The control range is 0 - 99% with a window of 1%
For even higher resolution, a decade switch (up to 5 decades) or a combination of decade switches with fine-tuning potentiometers can be provided.
Power regulator with display and controls
In addition to standard voltage and current regulation, units can be equipped with an additional control circuit to control power constancy.
Self-impedance
Serves to electronically simulate the changing intrinsic impedance of the unit (i.e., battery characteristics). The technical design is similar to that of a power regulator.
Indication of pre-entered settings
Pre-entered settings can be displayed using the button located next to the corresponding meter. This is a standard option for MCP and HCP units.
Electronic scan nominal value (ramp function). All interfaces of the PROBUS V system are also equipped with the possibility of programming the ramp function.
Spark sensor monitors sparking due to overload current/voltage with alarm, shutdown or spark counter.
Lock circuit for monitoring connected loads (e.g. door contacts)
When the blocking circuit is open, the unit will be disabled by cutting off the power supply. The unit can only be turned on after pressing the “restart” button (RESET).
Fast output power discharge – for example in connection with a blocking circuit.
Active down regulation for fast, controlled reduction of output voltage.
Other values of voltage and frequency of the power supply network. In the standard version, our units are designed for power supply parameters of 230V, 50Hz or 400V, 50Hz in the case of three-phase power. But most of our units can be modified to adapt to different power grids used in other countries.
Better isolation of power output and/or input
For special applications (for example, when operating devices on a high-voltage platform), standard block insulation may not be enough. We can supply units with insulation voltages up to > 200 kV.
Custom power output: For a number of our unit types, the output is located on the front panel as standard. As an option and upon request, it can be moved to the rear panel (for example, like this: or like this:).
Temperature controlled fan
The fan of the unit, cooled by forced air flow, turns on only when power consumption increases. This option is applicable only to a few models, unless there is a strict requirement for stability of current regulation.
Often, bipolar power supplies have a constant output voltage. The desire to construct an regulated one from an unregulated bipolar power supply at low cost usually does not lead to anything good, since this leads to an imbalance of the output voltages (in amplitude) of opposite polarities. To implement this option, it is necessary to significantly “weight” the scheme.
There is also an option when an electronic unit is added to a unipolar power supply, which generates a negative voltage from a positive one. But this version of a bipolar source also has an imbalance of opposite voltages and does not allow use in power supplies with continuously variable output voltage.
This article provides another original version bipolar power from unipolar having the right to exist. This is a prefix - built on an operational amplifier LM358, to a conventional unipolar power supply, which allows you to obtain a full bipolar output voltage.
Any power supply with a voltage of 7...30 volts can act as an input voltage source, and the output voltage will be 3...14.5 volts.
During operation, this divider does not distort the output parameters of a unipolar power supply. This divider attachment can withstand a load of up to 10 amperes without distorting the voltage, both in the positive and negative channels. For example, if a load with a current consumption of 9 amperes is connected in the negative circuit of a bipolar power source, and 0.2 amperes in the positive circuit, then the difference between the negative and positive voltage will be less than 0.01 volts.
It should be noted that only the presence of a regulator in a unipolar power supply can ensure a change in the output in a bipolar one, otherwise adjustment will be impossible.
Description of the attachment-divider of unipolar voltage into bipolar
(DA1) measures the potential difference between the common wire and the midpoint of the voltage divider assembled at resistances R1, R2, R3. When this difference changes, the LM358 op-amp leads to stabilization of the output voltage, decreasing it or increasing it.
When input voltage is applied to the circuit, capacitors C1 and C2 are charged at half the supply voltage. With a balanced load, these voltages will be the output voltage of a bipolar power supply.
Now let's analyze the situation when an unbalanced load is connected to the output of a bipolar power supply, for example, the load resistance in the positive circuit is significantly lower than the load resistance connected to the negative circuit.
Since a load is connected in parallel to capacitor C1 (diode VD1 and a small load resistance), capacitor C2 will be charged both through capacitor C1 and through the above-designated circuit (diode VD1 and a small load resistance).
For this reason, capacitor C2 will be charged with a higher voltage than capacitor C1, and this will lead to the fact that the negative voltage will be higher than the positive one. On the common wire, the voltage will increase relative to the midpoint of the voltage divider R1, R2, R3, where the voltage is 50% of the input.
This contributes to the emergence of a negative voltage at the output of the op-amp LM358 relative to the common wire. As a result, transistors VT2 and VT4 open and, similarly to the electrical circuit “diode VD1, small load resistance” in the positive electrical circuit, bypasses capacitance C2 in the negative circuit, which leads to a balance of the currents of both circuits (positive and negative)
Likewise, transistors VT1, VT3 will open if there is a load imbalance towards negative voltage.
and glow discharge cleaning
BIAS POWER SUPPLY “IVE-241S”
The main area of application of the secondary power supply is as part of vacuum processing equipment to ensure stable and controlled processes for applying functional coatings. The power supply unit “IVE-241S” has a negative output voltage polarity and is designed to supply a “bias potential” to the carousel with products during cleaning and coating processes, as well as to supply a stabilized voltage or current to sputtering magnetrons. The unit has a digital opto-isolated external control interface “RS-485”.
BASIC TECHNICAL DATA
Output power, W*.....20÷1000
0÷-1350
Output current adjustable, A*.....0.025÷1.3
Output voltage instability, %, no more**.....1.5
Output current instability, %, no more**.....2
Output power instability, %, no more**.....2
Switching frequency, kHz.....2-60
Maximum peak arc protection current adjustable in steps, A.....from 2 to 7
Arc protection voltage threshold level adjustable in steps, V..... from -4 to -95
Efficiency, not less.....0.83
Electrical power consumption, W.....1250
Block weight, kg.....13
482 x 415 x 140
Supply voltage.....220V-15%/+10%, 48-62Hz
* - Within the output current-voltage characteristic.
** - In the range of load changes from 20% to 100%.
Output current-voltage characteristic of "IVE-241S" at maximum power.
BIAS POWER SUPPLY "IVE-243"
The main area of application of the secondary power supply is as part of vacuum processing equipment to ensure stable and controlled processes for applying functional coatings. The IVE-243 power supply has a negative output voltage polarity and is designed to supply a “bias potential” to the carousel with products during cleaning and coating processes, as well as to supply magnetron sputtering sources with a stabilized voltage or current. The unit has an opto-isolated analog-to-digital interface for external control.
BASIC TECHNICAL DATA
Output power, W.....200÷3000
Output voltage adjustable, V.....-30÷-1350
Output current adjustable, A.....0.25÷3.5
Output voltage instability, %, no more than.....1.5
Maximum peak arc protection current, A.....8
Efficiency, not less.....0.85
Electrical power consumption, W.....3600
Block weight, kg.....18
Overall dimensions of the block, mm.....482 x 415 x 140
BIAS POWER SUPPLY "IVE-245MS"
The main area of application is as part of vacuum processing equipment to ensure stable and controlled processes for applying functional coatings. The IVE-245MS power supply has a galvanically isolated output voltage with negative polarity and is designed to supply a “bias potential” to the carousel with products during cleaning and coating processes, as well as to supply a stabilized voltage or current to sputtering magnetrons.
The power supply has three operating modes:
“operating mode 1” with output voltage -600V;
“operating mode 2” with output voltage -1200V;
“operating mode 3” with output voltage -200V.
The unit allows polarity reversal of the output voltage when operating in “modes 1, 2 and 3”, provided that the potential of the output circuits relative to the unit body does not exceed ±1500V. The unit is equipped with an “arc protection and frequency switching” module and a serial digital interface for external control “RS-485”.
BASIC TECHNICAL DATA
Mode No. 1
Output adjustable voltage, V.....-60÷-600
Output adjustable current, A....1÷15
Output current instability, %, no more than.....2.5
Output power instability, %, no more.....3
Output voltage switching frequency, kHz.....0; 4 ÷ 40
Maximum current"arc protection", A.....30
Maximum arc protection time, μs.....2
Mode No. 2
Output adjustable power, W.....300÷6000
Output adjustable voltage, V.....-120÷-1200
Output adjustable current, A.....0.25÷7.5
Output voltage instability, %, no more.....2
Output power instability, %, no more.....3.5
Switching frequencyoutput voltage, kHz.....0; 4 ÷ 40
Maximum current"arc protection", A.....20
Adjustable arc protection voltage, V.....9÷90
Maximum arc protection time, μs.....3
Mode No. 3
Output adjustable power, W.....300÷6000
Output adjustable voltage, V.....-20÷-200
Output adjustable current, A.....1÷40
Output voltage instability, %, no more.....2
Output current instability, %, no more.....2
Output power instability, %, no more than.....2.5
Switching frequencyoutput voltage, kHz.....0; 4 ÷ 40
Maximum arc protection current, A.....45
Maximum arc protection time, μs.....1.5
Efficiency, not less.....0.85
Electrical power consumption, W.....7800
Block weight, kg.....18
Overall dimensions of the block, mm.....482 x 415 x 140
Three-phase supply voltage.....380V-15%/+10%, 48-62Hz
Output current-voltage characteristic of "IVE-245MS" in modes No. 1 and No.2.
Output current-voltage characteristic of "IVE-245MS" in mode No. 3.
The "IVE-245MS" block is a secondary power supply with a transformerless network input operating at a conversion frequency of 45-55 kHz. It is based on assemblies of transistor converter cells, powered by a network from a common three-phase noise-suppressing network filter, regulated by a control module. Voltage conversion is carried out using three identical converter modules, each with a power of 2 kW, including a power factor corrector. Converter modules with six 200V outputs are connected in parallel in the block. To reduce electromagnetic interference transmitted to the power supply network, the converter modules are connected to it through a network RF filter module. The outputs of the unit's converter modules are output to the fan control and switching module, which switches operating modes 1, 2, 3 and further to the switch module, and then through a current sensor to the output connector, from which the output voltage is supplied to the load via an output cable. The formation of algorithms and processing of control signals is carried out in the control module, and their interface with the external interface is carried out by the signal interface module. The unit is equipped with a fan control and switching module, which maintains a constant thermal regime of the converter modules and increases the operating life of the fans, and also switches the “operating modes” of the unit to No. 1 - “medium voltage”, No. 2 - “high voltage”, and No. 3 - “low voltage”, through series-parallel switching of six outputs of converter modules, receives three levels of output voltage: -600V/-1200V/-200V. The conversion of DC voltage -600V/-1200V/-200V into a pulsating unipolar voltage with simultaneous high-speed protection that breaks the load power circuit from the converter modules in less than 3 μs is performed by the switch switch module. The block has 3.5-bit digital units for indicating output and reference (set) parameters: current, voltage, power, frequency and their regulation from a manual control console or from external control via an analog-digital interface, as well as LED indication of all operating modes and , respectively, their selection from the manual control console or from the interface.
BIAS POWER SUPPLY "IVE-247S"
The main area of application of the secondary power supply is as part of vacuum processing equipment to ensure stable and controlled processes for applying functional coatings. The power supply unit "IVE-247S" has a negative polarity of the output voltage and is designed to supply a "bias potential" and supply a stabilized voltage or current to magnetron sputtering sources. The unit can be equipped with an external control interface “RS-485”.
BASIC TECHNICAL DATA
Output power, kW.....0.8÷18
Output voltage adjustable, V.....-100÷-1350
Output current adjustable, A.....0.8÷20
Output voltage instability, %, no more.....3
Output current instability, %, no more.....3
Switching frequency, kHz.....2-40
Maximum arc protection current, A.....40
Efficiency, not less.....0.85
Electrical power consumption, kW.....24
Block weight, kg.....68
Overall dimensions of the block, mm.....284 x 860 x 400
Three-phase supply voltage.....380V-15%/+10%, 48-62 Hz
POWER SUPPLY FOR GLOW DISCHARGE CLEANING AND BIAS POTENTIAL “IVE-263”
The main area of application of the secondary power supply is as part of vacuum processing equipment to ensure stable and controlled processes for applying functional coatings. The IVE-263 power supply has a galvanically isolated output voltage with negative polarity and is designed to supply a “bias potential” to the carousel with products during cleaning and coating processes, as well as to supply magnetron sputtering sources with a stabilized voltage or current. The power supply has three operating modes: “operating mode 1” with an output voltage of 600V; “operating mode 2” with an output voltage of 1200V; “operating mode 3” with an output voltage of 200V. The unit allows polarity reversal of the output voltage when operating in “modes 1 and 3”. The unit can be equipped with an external control interface “RS-485”.
BASIC TECHNICAL DATA
Operating mode 1 Operating mode 2 Operating mode 3
Output power, W...................................200÷3000 200÷3000 200÷ 3000
Output voltage adjustable, V.........-60÷-600 -120÷-1200 -20÷-200
Output current adjustable, A........................0.7÷8 0.2÷4 0.7÷20
Maximum arc protection current, A...................28 20 38
Output voltage instability, %, no more.....2
Output current instability, %, no more.....3
Switching frequency, kHz.....1-40
Efficiency, not less.....0.85
Electrical power consumption, no more, W.....3500
Block weight, kg..... 18
Overall dimensions of the block, mm.....482 x 415 x 140
Supply voltage.....380V-15%\+10%, 48-62Hz
BIAS POWER SUPPLY "IVE-477S"
The functional purpose of "IVE-477S" is to perform all tasks of controlling and displaying information about the modes and parameters of the bias potential power supply system, as well as to generate control signals for the power unit and arc protection and frequency switching units. The formation of algorithms and processing of control signals are carried out in the control module. Information about the operating modes of the unit is displayed visually by the LED indication and control board, and the output and input parameters are displayed on the display modules located on the front panel of the unit and is output via a signal interface module in the digital serial code of the “RS-485” interface to the “External control” connectors. exiting to the rear panel. The signal interface module converts and galvanically isolates control and information signals going from the unit to the control and recording device and back, using a galvanically opto-isolated RS-485 interface, as well as their interface and transmission to the control module. In addition, the signal interface module switches control and information signals coming from manual controls. The first ones, located on the left of the signal interface module and the control module, belong to the first channel and control the power unit and the arc protection unit of the first channel. The second ones, located on the right of the signal interface module and the control module, belong to the second channel and control the line filter module, converter module and arc protection unit of the second channel located in it. The service power supply module installed in the unit provides all internal modules with the necessary standby and service voltages, including +5V voltage supplied to the power unit and mains voltage ≈220V supplied to two arc protection units. The pulse generation and fan control module controls the cooling fan and generates control pulse signals of a given duration to open the switch modules in the arc protection unit, ensuring, if possible, equality of positive and negative currents, and maintaining the duty cycle of control signals in the range from 0.3 to 0, 7.
